drm/i915: gen2: move error capture of IER to its correct place

While checking the error capture path I noticed that this register is
read twice for GEN2, so fix this and also move the read where it's done
for other platforms.
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -1054,9 +1054,6 @@ static void i915_capture_reg_state(struct drm_i915_private *dev_priv,
 		error->gfx_mode = I915_READ(GFX_MODE);
 	}
 
-	if (IS_GEN2(dev))
-		error->ier = I915_READ16(IER);
-
 	/* 2: Registers which belong to multiple generations */
 	if (INTEL_INFO(dev)->gen >= 7)
 		error->forcewake = I915_READ(FORCEWAKE_MT);
@@ -1080,6 +1077,9 @@ static void i915_capture_reg_state(struct drm_i915_private *dev_priv,
 	if (HAS_PCH_SPLIT(dev))
 		error->ier = I915_READ(DEIER) | I915_READ(GTIER);
 	else {
+		if (IS_GEN2(dev))
+			error->ier = I915_READ16(IER);
+		else
 			error->ier = I915_READ(IER);
 		for_each_pipe(pipe)
 			error->pipestat[pipe] = I915_READ(PIPESTAT(pipe));